SIM Swap Crypto Theft: Court of Appeal Ruling on Jurisdiction

The phone signal suddenly drops; no calls can be made and the internet cannot be reached. When the user finds out that the problem lies with the SIM card and obtains a new one, the account on the crypto asset platform turns out to be empty: the balance has been converted to USDT and sent to an external wallet address. The injured person often names the mobile operator and the crypto platform as defendants in the same lawsuit. So which court will hear a single case brought against these two defendants? The decision of the Diyarbakır Regional Court of Appeal 6th Civil Chamber dated 05.11.2026 gives an interesting answer to this question.

In its decision of 05.11.2026, Docket No. E.2026/1462, Decision No. K.2026/1492, the Diyarbakır Regional Court of Appeal 6th Civil Chamber set aside, ex officio and on the ground of jurisdiction, the judgment of the Diyarbakır 1st Court of First Instance for Commercial Matters that had upheld the claim on the merits, and returned the case to the court of first instance so that it could be sent to the consumer court where the lawsuit was originally filed.

📵 The signal dropped, the crypto account was emptied

According to the account in the petition, the signal of the claimant's mobile phone was suddenly cut during a certain time interval, and the claimant could no longer reach the internet or the telephone. Having learned that the problem might come from the SIM card, the claimant obtained a new SIM card; immediately afterwards, the claimant noticed that the assets in the accounts held on a crypto asset platform under two separate user numbers had been converted into their USD equivalent and transferred to other accounts.

The claimant filed a criminal complaint, and an investigation was opened at the Diyarbakır Chief Public Prosecutor's Office. According to the information gathered by the prosecutor's office:

The claimant asserted that no application for a SIM card change had been made, that no signature had been given, that the password had not been shared with anyone, and that no notification had been sent to the claimant by either the mobile operator or the crypto platform. The claimant requested that the amount withdrawn from the account be collected from the two defendants jointly and severally, together with statutory interest from the date of the incident.

🔁 The defences of the two defendants pointing at each other

Each defendant argued that the loss arose in the other's sphere.

The crypto platform argued that the case should have been filed before the competent Istanbul Courts of First Instance for Commercial Matters. On the merits, it stated that the username and password were entered correctly at login, that the verification codes sent to the registered telephone number and email address were used, and that the assets were then withdrawn to an external wallet not registered on the platform. According to the platform, protecting the password and personal information is the user's obligation, and the platform was not at fault in the incident.

The mobile operator, for its part, argued that the SIM card change was carried out not by itself but by a dealer acting as an independent merchant, and that it therefore had no standing to be sued and there was no causal link. According to the operator, it is the banks that are obliged to protect deposits; it also argued that the other defendant had created a security gap by failing to take the necessary measures on its web page. The operator also raised objections on jurisdiction and standing.

🏛️ From a refusal of jurisdiction to a judgment upholding the claim

The procedural history of the case is important for understanding the decision:

Without examining any of these objections on the merits, the Regional Court of Appeal took up jurisdiction ex officio, as a condition of the action relating to public order.

🧩 The Regional Court of Appeal: two separate legal relationships

The chamber first characterised the case: the dispute concerns compensation for the material loss suffered because assets were stolen from a crypto asset account as a result of a SIM card change made without consent. It then assessed the claimant's relationship with each of the two defendants separately.

The relationship with the crypto platform: There is no dispute between the parties that the claimant carried out crypto trading as an investor under the platform's terms of use. The chamber recalled that crypto assets were brought within the scope of regulation by Law No. 7518, published in the Official Gazette on 02.07.2024, amending Capital Markets Law No. 6362. According to the decision, a claimant acting for profit does not have consumer status in this relationship; and since the case was filed after this regulation entered into force, had it been brought only against the platform, the competent court would have been the commercial court of first instance.

The relationship with the mobile operator: The chamber stated that the subscription agreement between the claimant and the operator must be assessed separately. The definitions of consumer, provider and consumer transaction in Article 3 of Consumer Protection Law No. 6502, the jurisdiction rule in Article 73 and the provision in Article 83 that "regulation in other laws does not prevent a transaction from being treated as a consumer transaction" were considered together. Within this framework, the subscription relationship is a consumer transaction falling within the specialised field of the consumer court.

🧲 The pull of the specialised court

The core of the decision is its assessment of how the competent court is determined where claims are joined (objective joinder of claims). At this point the chamber set out the following principles:

In this case, claims arising from the same incident were put forward against both defendants in a single lawsuit. The relationship between the claimant and the platform falls within the jurisdiction of the commercial court of first instance, and the relationship with the operator within that of the consumer court. According to the chamber, the court competent to hear the whole dispute in this situation is the consumer court, which is the specialised court. It found it erroneous that the commercial court of first instance went into the merits instead of giving a decision of lack of jurisdiction directed to the Diyarbakır 1st Consumer Court, where the case was originally filed.

As a result, the appeals were accepted ex officio on public order grounds, without examining the grounds relating to the merits; the first instance judgment was set aside under Article 353/1-a-3 HMK, the action was dismissed on the ground of jurisdiction, and the case was returned to the court of first instance so that it could be sent to the consumer court following the procedure in Article 20/1 HMK. It was stated that there is no room for now to examine the appeal grounds relating to the merits.

🔎 What does it mean for crypto victim cases?

The decision contains no finding on liability on the merits; whether the mobile operator is responsible for the dealer's act and whether the crypto platform is responsible for the withdrawal to the external wallet will be assessed in the proceedings before the consumer court. Even so, several aspects of the decision stand out:

For the assessment on the merits in a case brought against the platform by a user whose crypto account was emptied by a SIM card change, see our article on Court of Cassation 3rd Civil Chamber 2026/2209TR; a different view of the jurisdiction debate between a crypto platform and a user can be found in our article on Ankara Regional Court of Appeal 21st Civil Chamber 2026/957TR.

❓ Frequently asked questions

For detailed information and legal support, you can contact Savun Law & Consultancy. Contact details are on the contact page; other decisions on crypto asset and investment disputes can be followed on the Precedent DecisionsTR page.